Investtigation of specifications of υSystan dust storms and assessment of sediment load using satellite image processing and field measurments
2008
Iranmanesh, Fazel | Arabkhedri, Mahmud | Jalali, Nader | Partovi, Afshim | Lotfolah zadeh, Dadvar | Tabatabaei, Mahmud reza | Rashki, Alireza
This study has been done to determine the origin of dust storm and spreading of dust using satellite image processing techniques. Since dust storms occur in large area and can transport a lot of dusts in long distances, large-scale repeatable images were needed. Besides the above-mentioned specification, the MODIS(1) sensor from TERRA satellite receives wide wavelengths of electromagnetic, which can be used to meet the purposes of this study. Five images of MODIS taken in 2001 were used in this project to meet the above purposes. An image of Landsat ETM+ taken in 2001 was also used to prepare NDVI(2).Measurements on the images of dust storm showed that the directions of dominant winds in Sistan's dust storm are between 339 to 346 degrees. These directions coincided with the directions of erosive winds in Zabol synoptic meteorological station. Visual interpretation on the origin and the storm paths of dust storm showed that the dust storm starts over Hamon Sabory Lake, and long passageways with heavy dust are separated from light dust, and to continue towards Iran, Afghanistan and Pakistan. These passageways seem like cones the head of which are at the origin and the bases towards the opposite direction. On the other hand, the extracted Normalized Difference Vegetation Index (NDVI) with its high values (0.24) showed condensed vegetation in southern shore area of Sabory lake. The comparison between the spectral signature of samples with heavy and light dust showed that, it had a little variation with each other. But afterwards, the passageways with heavy and light dust were formed. In addition, eastern and western of pavement, Hamon lakes and sand dune is the main center of dust storm.
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